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Average Atomic Mass
AVERAGE ATOMIC MASS: The average mass of the naturally occurring isotopes of an element
• The mass number of elements changes constantly. To find the average atomic mass, we take into account the amount of time the element has each mass number.
• On the Periodic Table of the Elements, the atomic mass is listed as a decimal. Why? It’s the average mass of all the naturally occurring isotopes of an element.
UNIT 2: ATOMIC STRUCTURE © 43
